Field of the Invention
The present invention relates to a supplemental charging control device for an electric vehicle, which carries out supplemental charging of a battery for auxiliary equipment.
Description of the Related Art
In general, an electric vehicle includes a high-voltage drive battery that supplies electrical power to a drive source, and a low-voltage battery for auxiliary equipment or auxiliary devices, which supplies electrical power to the auxiliary devices and to an ECU (Engine Control Unit). When the ECU is activated by supply of electrical power to the ECU from the auxiliary equipment battery, under the control of the ECU, supply of electrical power to the drive source from the drive battery commences, and the electric vehicle is started.
Incidentally, if the auxiliary equipment battery goes dead, supply of electrical power to the ECU cannot be carried out. Consequently, the ECU is not activated, and supply of electrical power from the drive battery to the drive source is not carried out, so that the electric vehicle cannot be started up.
In order to avoid the battery going dead in this manner, in Japanese Patent No. 5293841, a technique is disclosed for intermittently monitoring the voltage of an auxiliary equipment battery during suspension of traveling, with the object of preventing problems in starting the vehicle due to a voltage reduction of the auxiliary equipment battery during suspension of traveling, and in the case that the voltage falls below a predetermined voltage, supplemental charging to the auxiliary equipment battery is carried out. Further, in Japanese Laid-Open Patent Publication No. 2011-062018, a technique is disclosed in which supplemental charging of an auxiliary equipment battery is implemented when a voltage value of the auxiliary equipment battery falls below a predetermined value. Furthermore, in Japanese Laid-Open Patent Publication No. 2010-206885, a technique is disclosed for intermittently monitoring the voltage of an auxiliary equipment battery during suspension of traveling, in order to prevent a situation where the vehicle cannot travel due to a voltage reduction of the auxiliary equipment battery during suspension of traveling, and in the case that the voltage falls below a predetermined voltage, supplemental charging to the auxiliary equipment battery is carried out.